Other slides in this set

Slide 2

Preview of page 2

Here's a taster:

Contents
· Energetics
· Kinetics
· Equilibria
· Redox Reactions
· Group VII, The Halogens…read more

Slide 3

Preview of page 3

Here's a taster:

Energetics
· Enthalpy Change (H )
· Calorimetry
· Hess's Law
· Calculation of Bond Enthalpies
· Using Bond Enthalpies…read more

Slide 4

Preview of page 4

Here's a taster:

Enthalpy change (H )
· All chemical reaction involve a transfer of energy. Chemists call this
energy change as the enthalpy change of the reaction.
· Exothermic reactions have a negative enthalpy change, that is they
transfer energy to their surroundings.
· Endothermic reactions have a positive enthalpy change, that is they
take in energy from their surroundings.
· The standard enthalpy change of combustion is the enthalpy change
when 1 mole of a compound is burnt completely in oxygen under
standard conditions (298K and 100kPa), all reactants and products
being in their standard state.
· The standard enthalpy change of formation is the enthalpy change
when 1 mole of a compound is formed from its elements under
standard conditions (298K and 100kPa), all reactants and products
being in their standard state.…read more

Slide 5

Preview of page 5

Here's a taster:

Calorimetry
· The enthalpy change can be calculated from the
temperature change in a reaction using the equation:
­ q = mcT
· q is the enthalpy change (J), m is the mass (g) c is the specific heat
capacity J g-1K-1, T is the temperature change in K.
· Example: excess of magnesium was added to 100cm3 of
2M CuSO4 solution. The temperature increased by 45K.
The specific heat capacity of water is 4.2 J g-1K-1
· Find q using the above equation
­ q = 100 x 4.2 x 45 =18810J
· Find the amount in moles that reacted
­ 2X100/1000 =0.2
· Scale the enthalpy change for one mole of CuSO4
­ 18810/0.2 = 94050J =94 kJ mol-1…read more

Slide 6

Preview of page 6

Here's a taster:

Hess's Law
· Hess's law states that, if a reaction can take place by
more than one route and the initial and final conditions
are the same for each route.
route 1
· N2(g) + 3H2(g) Hf 2NH3 (g)
route 2 H2
H1
2N(g) + 6H(g)
· Hf = H1 + H2…read more

Slide 7

Preview of page 7
Preview of page 7

Slide 8

Preview of page 8
Preview of page 8

Slide 9

Preview of page 9
Preview of page 9

Slide 10

Preview of page 10
Preview of page 10

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all resources »